Brynn McLean was the daughter of Liam Mclean and the twin sister of Connor McLean. Like her brother, she was a purebred werewolf, born with the curse rather than being infected with it. The two of them were looking for a way to make their transformations permanent and asked for Josh's help into do so.
She is portrayed by actress Tracy Spiridakos.
In Episode 5 "Addicted To Love", Brynn convinces Nora to embrace her 'inner wolf' and kill Will.
In Episode 7, "The Ties That Blind", she and her brother Connor discover they've been betrayed and kidnap Cecilia, using her as bait to lure Aidan out into the woods on the night of their turn. Aidan manages to escape Josh, Nora, and Connor in their wolf forms as Cecilia sacrifices herself. The next morning, Brynn, Josh and Nora watch as Aidan kills Connor; angrily, Aidan warns Brynn to leave Boston.
While at her parents' home for her mother's birthday, Nora tells Josh she overpowered and killed Brynn one night when Brynn was planning to kill a boy she had met for fun.